Haematology & Medical Oncology Emergencies
Interpret blood-count patterns and recognise time-critical complications of cancer and its treatment.
Quick revision ↓ Medical Dictionary
01Read the blood count as a pattern
Assess haemoglobin, cell indices, white-cell differential and platelets together, comparing previous results. Reticulocytes help distinguish marrow response from impaired production. A blood film can clarify abnormal cells or haemolysis. Multiple cytopenias suggest a different differential from isolated iron deficiency. Interpret the count with bleeding, infection, medications and systemic symptoms rather than treating every low value as the same nutritional problem.
02Investigate haemolysis and bleeding
Haemolysis may produce reticulocytosis, raised LDH and indirect bilirubin with reduced haptoglobin, but each test needs context. Thrombocytopenia has causes including reduced production, immune destruction, consumption and sampling artefact. Bleeding severity depends on cause, platelet function, coagulation and clinical context, not just one count. Thrombocytopenia with haemolysis, renal or neurological abnormalities can signal a thrombotic microangiopathy requiring urgent specialist review.
03Recognise neutropenic sepsis
A patient receiving systemic anticancer treatment who becomes unwell needs urgent assessment for neutropenic infection, even without a dramatic fever. Do not wait for a full confirmatory picture before escalating through the emergency pathway. Obtain appropriate samples and prompt empiric treatment under local guidance. Ask about treatment timing, central lines, mucosal symptoms and previous resistant organisms while assessing haemodynamic and respiratory stability.
04Identify other cancer emergencies
New back pain with weakness, sensory change or bladder dysfunction in a patient with cancer raises concern for metastatic spinal cord compression. Urgent imaging and specialist care can preserve function. Tumour lysis may cause hyperkalaemia, hyperphosphataemia, hypocalcaemia and renal injury, particularly around treatment of high-burden susceptible malignancy. Hypercalcaemia can cause dehydration, confusion and constipation and also requires cause-specific monitored treatment.
05Support continuing care
A suspected malignancy needs an appropriate diagnostic pathway, careful explanation and attention to symptoms and function. Avoid promising a diagnosis from a nonspecific tumour marker alone. Review thrombosis risk, nutrition, pain and treatment goals with the specialist team. Palliative care can accompany disease-directed treatment and should address physical, psychological and family needs. Coordinate follow-up so abnormal counts or red-flag symptoms are not lost between services.
High-Yield Revision
- Interpret all cell lines and the reticulocyte response.
- An unwell chemotherapy patient may have neutropenic sepsis without a high fever.
- New neurological symptoms with cancer-related back pain require urgent action.
Common Pitfalls
- Do not wait for a tumour marker to diagnose a spinal emergency.
- Do not assume thrombocytopenia is harmless because visible bleeding is absent.
References & Further Reading
Read the relevant guideline sections alongside these original clinical teaching cases. Local pathways, available services and individual patient factors determine care.
Reference review: 27 September 2026. Consult current local protocols for prescribing, procedures and escalation.